Sunday, April 15, 2018

Pain and stiffness after shoulder arthroscopy - is Propionibacterium a factor?

These authors point out that Propionibacterium are suspected are often recovered from deep cultures at the time of revision for failed arthroplasty. They sought to identify Propionibacterium in revisions for shoulder arthroscopy failures due to pain and stiffness.

They prospectively collected data on all shoulder arthroscopies performed by the senior author from January 1, 2009, until April 1, 2013. A total of 1,591 shoulder arthroscopies were performed during this period, 68 (4.3%) of which were revision procedures performed for pain, stiffness, or weakness. Cultures were taken in all revision shoulder arthroscopy cases performed for pain, stiffness, or weakness. None of these patients exhibited overt clinical signs of infection such as fever or wound drainage. Although all of the patients had pain and complained of stiffness, none showed significant range-of-motion limitations characteristic of the diagnosis of adhesive capsulitis. For all patients, 2 intraoperative specimens were prospectively collected, submitted for culture, and held for a minimum of 14 days by the hospital microbiology laboratory. In all cases, tissue cultures were obtained from the synovium of the rotator interval, with additional cultures obtained from other focal areas of synovitis, from retained sutures or implants, and from the subacromial space. All cultures were kept as solid tissue, and the tissue was immediately placed in a culture swab container to ensure increased yield and to minimize contamination by eliminating any need for subsequent tissue transfer during the microbiology preparation

A total of 20 revision arthroscopies (29.4%) had positive culture findings, and 16 (23.5%) were positive for Propionibacterium. 32% of the male patients were culture positive while 13% of the female patients were culture positive. All shoulders with proven positive cultures were found to have evidence of synovitis on diagnostic arthroscopy.

In addition, 2 cultures were taken from each of a cohort of 32 primary shoulder arthroscopy cases without concern for infection. In the control group, 1 patient (3.2%) had P acnes growth.

The authors conclude that the presence of Propionibacterium in shoulders undergoing revision shoulder arthroscopy is higher than previously published. Propionibacterium may contribute to refractory postoperative pain and stiffness after shoulder arthroscopy.

Comment: This is an important study in that it indicates that Propionibacterium may be introduced at the time of arthroscopy, perhaps related to the passage of cannulas and suture from the skin through the dermis and into the joint. If this is the case, patients with prior arthroscopy may be at increased risk for Propionibacterium infection if a subsequent arthroplasty is carried out.

It is of note that in this study, only two tissues samples were submitted for culture. It is known that harvesting more specimens increases the chances of identifying Propionibacterium. Taking more specimens might have yielded a higher rate of culture positivity. It would be of interest to know how many shoulders had synovitis and negative cultures.
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